The Vector Core of the DF/HCC was established in 1998 with the specific mission to provide state-ofthe- art gene transfer technology and expert advice to DF/HCC investigators. The DF/HCC Vector Core is closely allied with investigators at the Harvard Gene Therapy Initiative who are focused on the development of new gene therapy vectors and associated technologies, so that as new advances in the area of vector development are made, they can be rapidly offered to Core users. The capabilities of this core include the rapid construction and characterization of a wide range of plasmid constructs, viral vectors, and genetically engineered tumor.cell lines suitable for tumor cell vaccination studies.